How do I turn off deinterlacing on OSSC PRO?

[WastingMoney]

I am trying to downscale a 480p video signal to 480i to use on my crt. The 480i mode has a ton of horizontal flickering/shimmering. Apparently this has something to do with the deinterlacing process. Is there any way to turn it off?

• This topic was modified 1 month ago by WastingMoney.

[Zacabeb]

What is happening is probably that the OSSC Pro is dropping every other line instead of blending them, leaving some detail only visible in every other field.

Try setting the scaling algorithm to GS Medium or Soft.

[WastingMoney]

I tried that and it didn’t change. Could a poor quality 15khz transcoder cause the shimmering? I bought this one.

[BuckoA51]

Exactly where is that converter in your setup? Are you placing it after the OSSC on the output of the extra AV card?

What is the source you are trying to convert? Does 480p to 240p produce a good image?

[WastingMoney]

I attach the transcoder to the AV out, then attach the composite out to the TV.

The source is my computer hdmi. The actual image quality is better than the cheap hdmi to composite I bought, but the image is also incredibly unstable with constant shimmering.

• This reply was modified 1 month ago by WastingMoney.
• This reply was modified 1 month ago by WastingMoney.

[marqs]

There’s no flicker filter at the moment, so any fine pitch high-contrast content like small text is subject to flicker. You could try 240p mode instead if loss of static resolution is acceptable.

[WastingMoney]

Is a rainbow strobe effect normal? It doesn’t just affect small text, it is apparent even in large mono-color areas. 240p mode does get rid of most of it. By “shimmering” I meant extreme dot crawl. I’m sorry for being non-descriptive.

Edit: It seems the problem is in fact with the transcoder.

If anyone knows how to get a better composite signal please let me know.

• This reply was modified 1 month ago by WastingMoney.
• This reply was modified 1 month ago by WastingMoney.
• This reply was modified 1 month ago by WastingMoney.

[Zacabeb]

I think you mean rainbow swirls or cross-color, which is misinterpretation of luma as chroma information causing false color in fine detail.

One of the remedies to it is adding a trap filter to the luma signal before encoding, which removes frequencies at and around that of the color subcarrier at the cost of sharpness. I assume that the transcoder in question has a weak or no trap filter. Since it has S-video out from what I can see, it’s technically possible to put a trap filter in line with the luma signal and then combine it with chroma into composite video after the transcoder.

Dot crawl or cross-luma in turn is the color subcarrier sneaking past the notch filter  that removes the color subcarrier from luma, causing a checkerboard pattern around color transitions. It is harder to do much about as it is primarily affected by the quality factor of the notch filter in the receiver.

• This reply was modified 3 weeks, 6 days ago by Zacabeb. Reason: Fixed some words to make better sense

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